The UFC 202 press conference lit the blue touch paper for what's now looking like one of the biggest grudge matches in recent memory.

Firstly, there was the usual charade of Conor McGregor arriving late. Again.

Then, just as McGregor was getting used to his chair on the stage, Diaz, acting on a signal from big brother Nick in the audience, got up and left, hurling a tirade of insults at McGregor and his team as he went.

Things escalated VERY quickly and those insults then turned into missiles, as bottles and even unopened cans of Monster Energy (the big ones) were fizzed into the crowd.

It was unsightly, it was unplanned and I'm sure both Diaz and McGregor will have their hands slapped for their actions.

But it also woke up fight week in a spectacular way.

I was fascinated to observe the body language between McGregor and Diaz this week, knowing the mind games McGregor loves to play. But right now, Diaz has been winning the mental game, too.

Conor has only ever looked rattled twice in the UFC, and both times were because of Diaz.

The first time was when he was stunned by a big one-two combination at UFC 196, then turned into the very thing he'd accused previous opponents of being - a 'panic wrestler'.

And on Wednesday he lost his head again, ignoring UFC president Dana White's calls to not throw the cans and hurling two of them into Diaz's entourage with all the ferocity of a baseball pitcher delivering a fastball.

The big question now is can McGregor regain his composure. Because against the man who took everything McGregor could throw at him, then submitted him last time out, he's going to need every ounce of it.